Chamber of horrors

Simple scandals are more eye-catching and create more outrage than big, complex frauds. As MPs' expenses drip out into the open, the case for the defence - such as it is - must start by accepting there have been dodgy dealings, for that is now palpably obvious. The plea, however, is that in the scale of swindlers even Westminster's worst are small fry, more Arthur Daley than Robert Maxwell.

Our silky-tongued defence counsel would concede that it was indeed blushworthy that one Lib Dem MP had claimed for eyeliner, before pointing out that many offices have some employees who obsessively claim for trivial things or chance their arm with costs half-related to work. He would go on to point out that while John Prescott's lavatory seats are easier to comprehend than the full size of Sir Fred Goodwin's pension, there is no doubt which costs the taxpayer more. The final plea in mitigation before judgment is that hysterical overreaction to the selective disclosure of the receipts in a newspaper with partisan leanings will do our democracy harm.

And indeed, that might well be true. An indiscriminate tide of indignant fury could submerge all the main parties and even the most conscientious public servants. A fury which, for instance, sees no distinction between genuine corruption and the prime minister's mundane arrangements to employ a cleaner jointly with his brother - arrangements "exposed" yesterday - will do public life no good, encouraging only the BNP and crackpot colonels who have never much liked democracy. The fact a guilty verdict may have unfortunate consequences, however, is not sufficient reason to reject it. Cast the supermops, the X-rated movies and the rest of the tittle-tattle to one side, and we are left with two uncomfortable truths. First, MPs collectively have set themselves indecent rules. Secondly, many among them have gone out of their way to exploit the rules in an indecent way; to pocket every penny they can.

The rules on second homes are particularly flawed. Introduced during the Thatcher era, the Commons has ever since regarded them as a means of sweetening the pill of pay restraint. Instead of merely covering rent, the rules cover mortgages, furnishing - hence all those receipts for magnolia carpets and plant pots - and also allow retiring MPs to pocket the uplift in value, thereby converting a supposed living allowance into a fund for property speculation. Some parliamentarians grumble their basic salary is not sufficient, and compared to many top London professionals their wage is not high. But they earn far more than most of their constituents. If they want to make the case for a rise, they should do so out in the open.

Instead, the majority at Westminster closed ranks, hiring lawyers and taking the information commissioner to the high court to prevent the system being exposed to daylight. Only the defeat of these efforts spurred new interest in reform. Even before yesterday, two senior ministers had been caught claiming a room in a relative's house was their principal address, while suggesting properties they owned in their own name were second homes, which are covered under the scheme. It now falls to the business secretary, Peter Mandelson, to justify landing taxpayers with a bill to repair a home he was about to sell, and to the chancellor to explain whether his indecisiveness about whether he was based in London or Scotland had anything to do with avoiding stamp duty. The fact that other ministers - Ed Miliband, Alan Johnson - have modest expenses and nothing to explain only makes the position of the energetic claimers more difficult.

The opposition is being unusually measured, no doubt it is well aware it will soon have its own problems. The shaming of Westminster helps no one and weakens democracy. Not even the best advocate, though, will persuade anybody that it is not deserved.